Purification and biological effects of Araucaria angustifolia (Araucariaceae) seed lectin

This paper describes the purification and characterization of a new N-acetyl-d-glucosamine-specific lectin from Araucaria angustifolia (AaL) seeds (Araucariaceae) and its anti-inflammatory and antibacterial activities. AaL was purified using a combination of affinity chromatography on a chitin column and ion exchange chromatography on Sephacel-DEAE. The pure protein has 8.0kDa (SDS-PAGE) and specifically agglutinates rabbit erythrocytes, effect that was independent of the presence of divalent cations and was inhibited after incubation with glucose and N-acetyl-d-glucosamine. AaL showed antibacterial activity against Gram-negative and Gram-positive strains, shown by scanning electron microscopy. AaL, intravenously injected into rats, showed anti-inflammatory effect, via carbohydrate site interaction, in the models of paw edema and peritonitis. This lectin can be used as a tool for studying bacterial infections and inflammatory processes.     

Linking Biodiversity,the Environment and Ecosystem Functioning: Ecological Functions of Dung Beetles Along a Tropical Elevational Gradient

Biodiversity loss and anthropogenic environmental changes are known to impact ecosystem functions and services. However, there are still some uncertainties such as confounding environmental factors other than community attributes that affect ecosystem functioning. Our goal was to understand what factors influence the performance of Scarabaeinae dung beetle functions, testing the hypothesis that both community attributes and environmental variables influence the performance. Toward this aim, we collected dung beetles along an elevational gradient (800–1400 m a.s.l.) in the Espinhaço mountain range (Brazil) and quantified dung beetle functions, that is, dung removal, soil excavation and secondary seed dispersal. We recorded data on environmental factors related to climate, soil and vegetation and evaluated their effects on dung beetle functions. Dung beetle ecological functions declined with elevation and the decrease was more pronounced than richness, indicating that there are other factors involved in functions performance besides diversity of beetles. Indeed, we found that the ecological functions measured were dependent on both dung beetle community attributes and environmental factors. Climate, soil and vegetation influenced dung beetle function performance as much as richness, abundance and body size. Dung beetle functional diversity did not explain any of the functions measured. Our study demonstrates that ecological functions are directly influenced by both community attributes and environmental variables and confirms the link between biodiversity, environment and ecosystem functioning.     

Water scarcity in Brazil: part 1—regionalization of the AWARE model characterization factors

The International Journal of Life Cycle Assessment - This paper presents the regionalized water scarcity characterization factors (CFs) of the available water remaining (AWARE) model, which was...     

Stomach content analyses of Simulium perflavum Roubaud 1906 (Diptera: Simuliidae) larvae from streams in Central Amazônia, Brazil

Stomach contents of Simulium perflavum Roubaud larvae were analyzed and compared with plankton and periphyton collected in five streams, in Central Amazonia (Manaus and Presidente Figueiredo counties), in Sep./Oct.1996 (dry season) and Feb./Mar. 1997 (rainy season). A total of 1,400 last-instar larvae were dissected; the stomach contents were analyzed using different methods: fresh and after oxidation. A total of 87 taxa (algae, diatoms and rotifers) were found in the stomach contents. In each stream, qualitative samples of plankton and periphyton were collected; these were mounted between slides and cover slips. A total of 94 taxa of plankton and 54 taxa of periphyton were collected. One species of Rotifera was present in the stomach contents, plankton and periphyton. Cluster analysis based on species composition of the organisms present in the stomach contents grouped the streams into two major groups, each belonging to a different drainage area. Correlations based on presence/absence of species of microalgae in the stomach contents, plankton and periphyton indicated significant associations (p<0.05) between stomach contents and plankton and between plankton and periphyton (z test); the Sorensen coefficient and cluster analysis corroborate the same associations.     

The deubiquitinase emperor's thumb is a regulator of apoptosis in Drosophila

We have characterized the gene emperor's thumb (et) and showed that it is required for the regulation of apoptosis in Drosophila. Loss-of-function mutations in et result in apoptosis associated with a decrease in the concentration of DIAP1. Overexpression of one form of et inhibits apoptosis, consistent with et having an anti-apoptotic function; however, overexpression of a second form of et induces apoptosis, indicating that the two forms of et may have competing functions. et encodes a protein deubiquitinase, suggesting it regulates apoptosis by controlling the stability of apoptotic regulatory proteins.     

Salt-induced changes on H<Superscript>+</Superscript>-ATPase activity,sterol and phospholipid content and lipid peroxidation of root plasma membrane from dwarf-cashew (<Emphasis Type=Italic>Anacardium occidentale</Emphasis> L.) seedlings

The effects of NaCl stress on the growth, water relation, gas exchange, tissue mineral content, and on H⁺-ATPase activity, lipid composition and peroxidation of root plasma membrane-enriched fractions of two genotypes (CCP06 and BRS189, sensitive and tolerant to salt stress, respectively) of dwarf-precocious cashew were studied. Growth reduction was higher in CCP06 than in BRS189. Net photosynthesis decreased in both genotypes, CCP06 being more affected. Roots of BRS189 accumulated higher amount of Na⁺ than those of CCP06 at both salt treatments, whereas Cl⁻ increase was higher only at 8 dS m⁻¹. NaCl at 8 dS m⁻¹ did not modify the plasma membrane H⁺-ATPase activity in CCP06 roots, but significantly increased it in BRS189 roots. Lipid peroxidation was lower in BRS189 than in CCP06 roots. Salinity induced higher accumulation of proline in BRS189 roots. Total phospholipids and free sterols content increased significantly in root plasma membrane of CCP06. However, in BRS189, a slight reduction of free sterols content and no changes in total phospholipids content were observed. Thus, the results suggest that the ability of cashew seedlings to adapt to salt stress is, at least in part, dependent upon the maintenance of integrity and protection against oxidative damage of plasma membrane, which could favor the activation of plasma membrane H⁺-ATPase, as a cellular mechanism to regulate ion exclusion from the shoot.